Axial flow compressor rotor



June 24, 1958 R. A. PAETZ 2,840,299

AXIAL FLOW COMPRESSOR ROTOR Filed Sept. 22, 1952 [17 FE r7 KG? 115 0856 1?. E4572 t 2,840,29il Patented June 24,1958

AXIAL FLOW COMPRESSOR ROTOR Robert A. Paetz, University Heights, Ohio, assignor to Thompson Products, Inc., Cleveland, Ohio, a corporation of Ohio Application September 22, 1952, Serial No. 310,867

Claims. (Cl. 230134) This invention relates to a vaned rotor such as is used in axial flow air compressors for turbo-jet engines wherein each vane has an integral spoke anchored to a hub and to a rim. Specifically, the invention deals with a lightweight low inertia axial flow compressor rotor having individual spoked blades.

While this invention will be hereinafter specifically described as embodied in an axial flow air compressor for turbo-jet engines, it will be appreciated that the principles of this invention are generally applicable to vaned wheels and therefore the invention is not limited to the illustrated preferred embodiment.

Heretofore, rotors for axial flow air compressors in turbo-jet engines have been built up from a series of heavy solid disks with the blades or vanes radiating from the peripheries thereof and anchored thereto as by means of a dove-tailed lock. These disks materially added to the weight of the rotor and increased its inertia.

According to the present invention, each vane or blade of the rotor is now equipped with its own spoke and the spoked units are anchored at the inner ends of the spokes to a hub and at the inner ends of the blade portions to a rim. This rim is composed of lightweight sheet metal and not only confines the air flow in the same manner as .the peripheries of the heretofore used disks but also is extended to space the successive spoked wheels apart in correct relation for receiving the stator blades therebetween in each stage of the compressor. The spoked wheels of this invention materially reduce the weight of the rotor without sacrificing strength or rigidity and thereby provide a low inertia rotor assembly which is capable of fast acceleration. Heretofore required disk forging, machining, dove-tail locking and the like expensive structures and assembly methods are avoided. The new wheels are easily assembled by inserting the blades through slots in the rims and by anchoring the spokes to the hub. If desired, the vanes can be welded to the rim around the rim slots. The hub can be composed of a pair of clamping rings receiving the root ends of the spokes therebetween preferably in radial slots thereof. The spoke blade units can be manufactured on roll forming machines, forged, or formed in any suitable manner from any desired material such as steel, aluminum, or alloy. It is also possible to form these units from powdered metal such as powdered iron infiltrated by copper. The rim can be a ring of aluminum or other lightweight sheet metal or can be machined from a forging of lightweight metal. The hub clamping rings can be aluminum, steel or the like metal. g

It is then an object of this invention to provide a low inertia stress-resisting bladed rotor adapted for an axial flow air compressor of a turbo-jet engine.

Another object of this invention is to provide a bladed rotor wherein the blades have their own individual spokes and are anchored in a rim and a hub.

Another object of the invention is to provide a bladed rotor having a plurality of annular rows of blades each equipped with a single rim and a plurality of spoked blade units anchored in the rim.

Another object is to provide a vaned wheel composed of spoked vanes. e

A still further object of the invention is to eliminate the heretofore required disks in axial flow compressor rotors.

A still further object of the invention is to provide an inexpensive lightweight bladed rotor.

Other and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheet of drawings which, by way of a preferred example only illustrate one embodiment of the invention.

Figure 1 is an end elevational view of a spoked blade rotor according to this invention;

Figure 2 is an isometric view of one blade units in the rotor of Figure 1;

Figure 3 is a fragmentary enlarged vertical crosssectional view, with parts in side elevation, of the rotor assembly taken along the line IIIIII of Figure 1; Figure 4 is a transverse cross-sectional view taken along the line IVIV of Figure 2; I Figure 5 is a fragmentary transverse cross-sectional view taken along the line VV of Figure 2; and

Figure 6 is a fragmentary view similar to Figure 5 but showing a modification including a vibration dampener.

As shown on the drawings: In Figure l, the reference numeral 10 designates genof the spoked erally an axial flow air compressor rotor assembly for a' turbo-jet engine. The rotor assembly 16 is composed of a plurality of spoked wheels 10a as shown in Figure-3. Y

Each wheel lfia includes a hub 11, a plurality of spoked blade units 13 radiating from the hub, and a rim 12 at the base end of the blade portions of the spoked units 13. It will be appreciated that the rim 12 comprises an annu lar drum having circumferentially spaced arcuate slots,

as will hereinafter become more apparent.

As best shown in Figure 2, the spoked blade units 13 are each composed of a blade portion 13a, a spoke portion 13b and an anchoring base 130. The bladeportions 13a have'a desired aerodynamic contour with a concave front face 14, and a convex back face 15 there being a shoulder 16 between each blade and the spoke 13b formed on the spoke and extending outwardly from the faces 14 and 15. The spoke 13b has a contour designed for structural strength. As shown in Figure 4 an oval shape is illustrated for the spoke 13b but any desired solid or hollow section can be used. The root 13c can be rectangular as shown in Figure 5 and have flat front and back faces 17 with end flat edges 18.

The rim 12 is a sheet metal band of frusto-conical contour and may have a leading end of smaller diameter than the trailing end. This contour may be provided if in successive stages of the axial flow compressor to be built up from the wheels 10a, the air flow passage is to be decreased in width. The smaller leading end of each rim 12 may have an inturned flange 12a with an outturned bead 12b projecting axially therefrom. The

larger trailing end of each rim may have a similar depending inturned flange but this flange is equipped with a groove 12d for receiving the. bead or projection 12b of the adjacent rim flange. Alternately, of course, the bead could be provided on the flange 12c and the groove could be provided on the flange 12a.

At spaced intervals around the periphery of the rim 12, slots 12e are provided for receiving the blades 13a therethrough. These slots are contoured to snugly receive the blades and the shoulder 16 will abut against the inner face of the rim on opposite sides of the blade 13a to correctly limit the extent of radial projection of inner edge of'the blade fits 'in the slot 12e and a Weld or braze bond 19 is provided between the rim and this inner end of the blade to integrally unite the rim with the blade and to also, seal otfthepressure side of the compressor to prevent leakage and circulation. In assembly, the blades 13a are slipped through the slots 12s until the, shoulders 16 abut the inner faces of the rim whereupon the blades are automatically positioned and the braze or weld bonds 19 are applied.

The ,hub 11 may be composed of a pair of opposed ring plates lla'clamped together by draw, bolts 11b. Eachplate 11a maybe radiallyv slotted at 20 to receive the ed'ges18'of the anchoring ends 13c of the spokes. The plates may be received ona shaft 21 and be notched to receive aJkey. 22 uniting the shaft and plates for corotation11 Any other suitable driving connection utilizing either shaft or the.rim can be used. Spacer sleeves such as 23 on the shaft212 may be positioned between, adjacent hubs 11 so as to correctly space the successive wheels a constituting, the rotor assembly 10.

In assembling the spokedunits into the hub, the inner plate 112: may be bottomed against the spacer sleeve 23, the anchoring ends 130 of the spokes depending from the rim are seated insuccessive grooves 20. The opposite hub plate 11a can then be placed on the shaft 21 so that the opposed edge 18 of each anchoring portion 130 may be received in a corresponding groove or slot 20. The draw bolt assemblies 11b can be inserted and tightenedfor securely clamping the portions 130 in affixed relation to the hub.

,Alternately, theanchoring ends 130 of the spoke could he brazed orwelded to'the hub.

If desired, the outer ends of the grooves 20, can terminate inwardly from the periphery of the plates 11a so as to provide lugs 24 overlying the portion 135 and snugly receiving the spoke portion 13b 'therebetween. These lugs will prevent radial displacement of the anchoring portions 13c.

As shown in Figure 6, in the event it is found desirable to dampen out vibrations without materially adding to the weight of the rotor assembly, the hub plates 11a of each wheel 10a can have fingers 25 radiating therefrom to carry rubber blocks 26 orother plastic vibration dampening material, against the spokes 13b at areas to stop vibration. Any suitable vibration dampener can be used including hubs ofincreased diameter to shorten the required spoke length.

contour complemental to the cross section of a blade, each blade having an individual supporting spoke of thicker cross section than that of said blade and forming a shoulder for abutting the inner surface of said drum around the edge of the associated arcuate slot, means fastening said spokes to said hub for holding each blade against radial displacementin said'slot and for c-o-rotation of the rotating member and blade, and fluid dampening means interposed between said central rotating member and said spoke to dampen vibration.

2. The axial. ilow compressor of claim 1 further characterized by said hub having finger structure bearing against said spoke and vibration dampening material disposed between said finger structure and said spoke.

3. In an axial flow. compressor including a drive shaft, a series of adjacent abutting rotors carried on said axial liow compressor, each rotor having a series of spaced spokes radiating from and fastened to said drive shaft, each spoke having a radially outer end extension comprising a radially extending blade, a separate one-piece continuous annular band-like rim disposed circumferentially around said spokes having spaced axial peripheries with l the spokes interiorly thereof and having a series of cir- It will be understoodthat successive wheels 10a in the rotor assembly 10' can have conical rims 12 of successively increasing diameter so as to provide a rotor rim with a small leading end and a large trailing end. It willfurther be understoodthat the blades 13a in the successive wheels 10a decrease in height from the first or inlet stage of the compressor.

From theabove description, it will thus that this invention now provides a rotor. especially adapted for the axial flow compressors of turbo-jet engines wherein a series of successive spoked wheels have mating rim flanges and are each composed of spoked vanesor blades anchored in the rims and also in a hub.

The rotor ofthis invention is a lightweight strong and rigid low inertia. unit.

, It will be understood that modifications and variations may be effected without departing from the scope ofthe novel concepts of the present invention.

Iclaim-as my'inventionr l 1. In an axial flow compressor including a central rotating member, a rotor including a central hub carried on said rotating member, a plurality of circumferentially spaced radially extending'blades, a cylindrical drum with circumferentially spaced arcuate slots, eachslot having a be understood cumferentially spaced slots, each with one of said blades projecting therethrough and thercbeyond, said rim being held centered'b y and bottomed against said spokes about said" drive shaft and otherwise free from said drive shaft and with the rim cooperating with said spokes in maintaining said blades in radially spaced relation with their outermost ends projecting freely beyond the external surface of the rim, and means to connect said rim peripheries of the adjacent abutting rotors, thereby providing a continuous unbroken outer surface defined by said rims.

4. In an axial how compressor including a central rotating member, a rotor including a central hub carried on said rotating member, a plurality of circumferentially spaced radially extending blades, a cylindrical drum with circumferentially spaced arcuate slots, each slot having a contour complemental to the cross section of a blade, each blade having an individual supporting spoke of thicker cross section than that of said blade and forming a shoulder for abutting the inner surface of said drum around the edge of the associated arcuate slot, and means fastening said spokes to said hub for holding each blade against radial displacement in said slot and for co-rotation of the rotating member and blade.

5. In an axial flow compressor for a turbo-jct engine including a rotor Wheel mounted on a drive shaft which comprises a plurality ofcircumferentially spaced spoked blades having spoke and blade portions, said rotor Wheel having a hub connecting hub ends of said spoke portions to said drive shaft, a cylindrical drum with circumferentially spaced arcuate shaped slots, each slot having a contour complemental to the cross-section of a blade portion, said spoke portion having a thicker cross-section than that of said blade portion and forming a shoulder at the junction of the blade and spoke portions with the shoulders on said spoke portion abutting the inner surface of said drum around the edge of the associated arcuate slots and with said drum being secured to said spoked blades and being otherwise out of contact with said rotor wheel and said drive shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,264,877 Haigh Dec. 2, 1941 2,384,919 'Huber Sept. 18, 1945 2,398,140 Heppner Apr. 9, 1946 2,436,087 Benson Feb. 17, 1948 2,540,991 Price Feb. 6, 1951 2,542,251 Hueglin Feb. 20, 1951 2,583,875 Ostmar Jan. 29, 1952 (Other references on following page) 5 UNITED STATES PATENTS Bachle July 22, 1952 Howard Sept. 16, 1952 Stalker Sept. 13, 1955 Burgess Sept. 20, 1955 Stalker Dec. 4, 1956 6 FOREIGN PATENTS Great Britain Dec. 11, 1947 Great Britain May 20, 1949 Germany Mar. 13, 1952 France Apr. 9, 1941 France Sept. 6, 1950 

